This invention relates to a method and apparatus for shaping the proximal surface of a human tibia, employing a novel adjustable shaping guide, which enables resection to be accomplished without sacrifice of the anterior cruciate ligament.
In replacing a knee joint which has been damaged due to disease or trauma, it is very important that the prosthesis used to replace the damaged portion of the joint be properly aligned with respect to the bone to which the prosthesis is fixed. Particular problems are encountered when resection of the proximal surface of the tibia is required, in that most shaping instrumentation requires sacrifice of the anterior cruciate whereas in most replacements the stability of the knee with replacement implants in place would be significantly improved by retaining the ligament.
To enable a surgeon to shape the proximal tibia to receive a tibial component of a total knee joint prosthesis, Leo A. Whiteside, one of the named inventors herein, developed a method and apparatus for shaping a proximal tibial surface which is claimed in U.S. Pat. No. 4,467,801. That patent teaches the use of an intramedullary alignment guide which provides the surgeon with a means for determining the central long axis of the tibia and a means by which the surgeon can shape the proximal tibia relative to that axis by attaching a planer or similar shaping instrument to that alignment guide. The anterior cruciate ligament is generally sacrificed using that method and apparatus.